Ball-End Mill with a Loxodromic Cutting Edge

Russian Engineering Research - Attention focuses on the design of a ball-end mill whose spherical section has a loxodromic cutting edge. The grinding width and depth required to obtain the rake and...     

Precision of surfaces machined on a lathe with geometric errors

The precision attained in the shape and mutual position of cylindrical surfaces after machining may be assessed by means of a mathematical model. The effectiveness of the model is confirmed in practice.     

Sound-absorbing polyurethane foam for the auto industry

Ambient noise harms the human organism: it produces high levels of the stress hormones, disrupts the operation of the nervous system, provokes cardiovascular damage, and impairs hearing. In the creation of new noise-reducing materials, the goal is to increase porosity without loss of structural strength. With greater porosity and reduced thickness, acoustic insulation will be lighter, which is better for use in automobiles. In addition, the dynamic characteristics are improved, and vehicle assembly is simplified.

     

Laser Machining of Tool Steels

Russian Engineering Research - Laser quenching and application of wear-resistant powder to the cutting edge of a hob is considered, with careful positioning of the laser spot. Experimental data are...     

Producing Polydicyclopentadiene from Lower-Grade Dicyclopentadiene

Russian Engineering Research - Polymer samples based on polydicyclopentadiene produced from Russian dicyclopentadiene are investigated by thermogravimetric analysis and differential scanning...     

Annealing effect on reflectivity spectra of opal photonic crystals

We analyze broadband visible reflectivity spectra of opal photonic crystals annealed in an argon atmosphere and air. Scanning electron microscopic examination has shown that the crystals consist of close-packed spheres with a mean diameter in the range 200–290 nm. Incorporation of even small amounts of carbon (?0.5 wt %) increases the density of the opal matrix. The presence of carbon shifts the Bragg reflection peak of the opal and increases its intensity.     

Optical properties of three-dimensional magnetic opal photonic crystals

We have studied the optical properties of opal photonic crystals infiltrated with the M_0.35Zn_0.65Fe₂O₄ (M = Ni, Co) ferrites. The crystals consisted of amorphous SiO₂ nanospheres. The visible reflectivity spectra of the crystals were used to determine parameters of their photonic band gap and their refractive index.     

Secondary cluster ions Ge 2 − and Ge 3 − for improving depth resolution of SIMS depth profiling of GeSi/Si heterostructures

New possibilities of improving depth resolution of SIMS depth profiling of GeSi/Si heterostructures using a TOF.SIMS-5 spectrometer are discussed. Contributions of ion sputtering artifacts and instrumental effects to depth resolution were analyzed in detail using a Talysurf CCI-2000 optical profilometer to control the shape and roughnesses of the sputtering crater bottom. It was found that the use of Cs⁺ ions for sputtering makes it possible to minimize roughness development during depth profiling of GeSi/Si structures to depths of 1–1.5 μm. It was shown that the use of secondary cluster ions Ge₂⁻ and Ge₃⁻ instead of Ge₁⁻ and Ge⁺ allows narrowing the transition regions in measured profiles.